xref: /llvm-project-15.0.7/libcxx/include/tuple (revision ae2ae84f) 
1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP_TUPLE
11#define _LIBCPP_TUPLE
12
13/*
14    tuple synopsis
15
16namespace std
17{
18
19template <class... T>
20class tuple {
21public:
22    explicit(see-below) constexpr tuple();
23    explicit(see-below) tuple(const T&...);  // constexpr in C++14
24    template <class... U>
25        explicit(see-below) tuple(U&&...);  // constexpr in C++14
26    tuple(const tuple&) = default;
27    tuple(tuple&&) = default;
28    template <class... U>
29        explicit(see-below) tuple(const tuple<U...>&);  // constexpr in C++14
30    template <class... U>
31        explicit(see-below) tuple(tuple<U...>&&);  // constexpr in C++14
32    template <class U1, class U2>
33        explicit(see-below) tuple(const pair<U1, U2>&); // iff sizeof...(T) == 2 // constexpr in C++14
34    template <class U1, class U2>
35        explicit(see-below) tuple(pair<U1, U2>&&); // iff sizeof...(T) == 2  // constexpr in C++14
36
37    // allocator-extended constructors
38    template <class Alloc>
39        tuple(allocator_arg_t, const Alloc& a);
40    template <class Alloc>
41        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, const T&...);          // constexpr in C++20
42    template <class Alloc, class... U>
43        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, U&&...);               // constexpr in C++20
44    template <class Alloc>
45        tuple(allocator_arg_t, const Alloc& a, const tuple&);                             // constexpr in C++20
46    template <class Alloc>
47        tuple(allocator_arg_t, const Alloc& a, tuple&&);                                  // constexpr in C++20
48    template <class Alloc, class... U>
49        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, const tuple<U...>&);   // constexpr in C++20
50    template <class Alloc, class... U>
51        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, tuple<U...>&&);        // constexpr in C++20
52    template <class Alloc, class U1, class U2>
53        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, const pair<U1, U2>&);  // constexpr in C++20
54    template <class Alloc, class U1, class U2>
55        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, pair<U1, U2>&&);       // constexpr in C++20
56
57    tuple& operator=(const tuple&);                                                       // constexpr in C++20
58    tuple& operator=(tuple&&) noexcept(is_nothrow_move_assignable_v<T> && ...);           // constexpr in C++20
59    template <class... U>
60        tuple& operator=(const tuple<U...>&);                                             // constexpr in C++20
61    template <class... U>
62        tuple& operator=(tuple<U...>&&);                                                  // constexpr in C++20
63    template <class U1, class U2>
64        tuple& operator=(const pair<U1, U2>&); // iff sizeof...(T) == 2                   // constexpr in C++20
65    template <class U1, class U2>
66        tuple& operator=(pair<U1, U2>&&); // iff sizeof...(T) == 2                        // constexpr in C++20
67
68    template<class U, size_t N>
69        tuple& operator=(array<U, N> const&) // iff sizeof...(T) == N, EXTENSION
70    template<class U, size_t N>
71        tuple& operator=(array<U, N>&&) // iff sizeof...(T) == N, EXTENSION
72
73    void swap(tuple&) noexcept(AND(swap(declval<T&>(), declval<T&>())...));               // constexpr in C++20
74};
75
76
77template<class... TTypes, class... UTypes, template<class> class TQual, template<class> class UQual> // since C++23
78  requires requires { typename tuple<common_reference_t<TQual<TTypes>, UQual<UTypes>>...>; }
79struct basic_common_reference<tuple<TTypes...>, tuple<UTypes...>, TQual, UQual> {
80  using type = tuple<common_reference_t<TQual<TTypes>, UQual<UTypes>>...>;
81};
82
83template<class... TTypes, class... UTypes>                                // since C++23
84  requires requires { typename tuple<common_type_t<TTypes, UTypes>...>; }
85struct common_type<tuple<TTypes...>, tuple<UTypes...>> {
86  using type = tuple<common_type_t<TTypes, UTypes>...>;
87};
88
89template <class ...T>
90tuple(T...) -> tuple<T...>;                                         // since C++17
91template <class T1, class T2>
92tuple(pair<T1, T2>) -> tuple<T1, T2>;                               // since C++17
93template <class Alloc, class ...T>
94tuple(allocator_arg_t, Alloc, T...) -> tuple<T...>;                 // since C++17
95template <class Alloc, class T1, class T2>
96tuple(allocator_arg_t, Alloc, pair<T1, T2>) -> tuple<T1, T2>;       // since C++17
97template <class Alloc, class ...T>
98tuple(allocator_arg_t, Alloc, tuple<T...>) -> tuple<T...>;          // since C++17
99
100inline constexpr unspecified ignore;
101
102template <class... T> tuple<V...>  make_tuple(T&&...); // constexpr in C++14
103template <class... T> tuple<ATypes...> forward_as_tuple(T&&...) noexcept; // constexpr in C++14
104template <class... T> tuple<T&...> tie(T&...) noexcept; // constexpr in C++14
105template <class... Tuples> tuple<CTypes...> tuple_cat(Tuples&&... tpls); // constexpr in C++14
106
107// [tuple.apply], calling a function with a tuple of arguments:
108template <class F, class Tuple>
109  constexpr decltype(auto) apply(F&& f, Tuple&& t); // C++17
110template <class T, class Tuple>
111  constexpr T make_from_tuple(Tuple&& t); // C++17
112
113// 20.4.1.4, tuple helper classes:
114template <class T> struct tuple_size; // undefined
115template <class... T> struct tuple_size<tuple<T...>>;
116template <class T>
117 inline constexpr size_t tuple_size_v = tuple_size<T>::value; // C++17
118template <size_t I, class T> struct tuple_element; // undefined
119template <size_t I, class... T> struct tuple_element<I, tuple<T...>>;
120template <size_t I, class T>
121  using tuple_element_t = typename tuple_element <I, T>::type; // C++14
122
123// 20.4.1.5, element access:
124template <size_t I, class... T>
125    typename tuple_element<I, tuple<T...>>::type&
126    get(tuple<T...>&) noexcept; // constexpr in C++14
127template <size_t I, class... T>
128    const typename tuple_element<I, tuple<T...>>::type&
129    get(const tuple<T...>&) noexcept; // constexpr in C++14
130template <size_t I, class... T>
131    typename tuple_element<I, tuple<T...>>::type&&
132    get(tuple<T...>&&) noexcept; // constexpr in C++14
133template <size_t I, class... T>
134    const typename tuple_element<I, tuple<T...>>::type&&
135    get(const tuple<T...>&&) noexcept; // constexpr in C++14
136
137template <class T1, class... T>
138    constexpr T1& get(tuple<T...>&) noexcept;  // C++14
139template <class T1, class... T>
140    constexpr const T1& get(const tuple<T...>&) noexcept;   // C++14
141template <class T1, class... T>
142    constexpr T1&& get(tuple<T...>&&) noexcept;   // C++14
143template <class T1, class... T>
144    constexpr const T1&& get(const tuple<T...>&&) noexcept;   // C++14
145
146// 20.4.1.6, relational operators:
147template<class... T, class... U> bool operator==(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14
148template<class... T, class... U> bool operator<(const tuple<T...>&, const tuple<U...>&);  // constexpr in C++14, removed in C++20
149template<class... T, class... U> bool operator!=(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14, removed in C++20
150template<class... T, class... U> bool operator>(const tuple<T...>&, const tuple<U...>&);  // constexpr in C++14, removed in C++20
151template<class... T, class... U> bool operator<=(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14, removed in C++20
152template<class... T, class... U> bool operator>=(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14, removed in C++20
153template<class... T, class... U>
154  constexpr common_comparison_category_t<synth-three-way-result<T, U>...>
155    operator<=>(const tuple<T...>&, const tuple<U...>&);                                  // since C++20
156
157template <class... Types, class Alloc>
158  struct uses_allocator<tuple<Types...>, Alloc>;
159
160template <class... Types>
161  void
162  swap(tuple<Types...>& x, tuple<Types...>& y) noexcept(noexcept(x.swap(y)));
163
164}  // std
165
166*/
167
168#include <__assert> // all public C++ headers provide the assertion handler
169#include <__compare/common_comparison_category.h>
170#include <__compare/synth_three_way.h>
171#include <__config>
172#include <__functional/unwrap_ref.h>
173#include <__memory/allocator_arg_t.h>
174#include <__memory/uses_allocator.h>
175#include <__tuple>
176#include <__utility/forward.h>
177#include <__utility/integer_sequence.h>
178#include <__utility/move.h>
179#include <__utility/pair.h>
180#include <__utility/piecewise_construct.h>
181#include <__utility/swap.h>
182#include <compare>
183#include <cstddef>
184#include <type_traits>
185#include <version>
186
187// TODO: remove these headers
188#include <exception>
189#include <new>
190#include <typeinfo>
191
192#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
193#  pragma GCC system_header
194#endif
195
196_LIBCPP_BEGIN_NAMESPACE_STD
197
198#ifndef _LIBCPP_CXX03_LANG
199
200
201// __tuple_leaf
202
203template <size_t _Ip, class _Hp,
204          bool=is_empty<_Hp>::value && !__libcpp_is_final<_Hp>::value
205         >
206class __tuple_leaf;
207
208template <size_t _Ip, class _Hp, bool _Ep>
209inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
210void swap(__tuple_leaf<_Ip, _Hp, _Ep>& __x, __tuple_leaf<_Ip, _Hp, _Ep>& __y)
211    _NOEXCEPT_(__is_nothrow_swappable<_Hp>::value)
212{
213    swap(__x.get(), __y.get());
214}
215
216template <size_t _Ip, class _Hp, bool>
217class __tuple_leaf
218{
219    _Hp __value_;
220
221    template <class _Tp>
222    static constexpr bool __can_bind_reference() {
223#if __has_keyword(__reference_binds_to_temporary)
224      return !__reference_binds_to_temporary(_Hp, _Tp);
225#else
226      return true;
227#endif
228    }
229
230    _LIBCPP_CONSTEXPR_AFTER_CXX11
231    __tuple_leaf& operator=(const __tuple_leaf&);
232public:
233    _LIBCPP_INLINE_VISIBILITY constexpr __tuple_leaf()
234             _NOEXCEPT_(is_nothrow_default_constructible<_Hp>::value) : __value_()
235       {static_assert(!is_reference<_Hp>::value,
236              "Attempted to default construct a reference element in a tuple");}
237
238    template <class _Alloc>
239        _LIBCPP_INLINE_VISIBILITY constexpr
240        __tuple_leaf(integral_constant<int, 0>, const _Alloc&)
241            : __value_()
242        {static_assert(!is_reference<_Hp>::value,
243              "Attempted to default construct a reference element in a tuple");}
244
245    template <class _Alloc>
246        _LIBCPP_INLINE_VISIBILITY constexpr
247        __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a)
248            : __value_(allocator_arg_t(), __a)
249        {static_assert(!is_reference<_Hp>::value,
250              "Attempted to default construct a reference element in a tuple");}
251
252    template <class _Alloc>
253        _LIBCPP_INLINE_VISIBILITY constexpr
254        __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a)
255            : __value_(__a)
256        {static_assert(!is_reference<_Hp>::value,
257              "Attempted to default construct a reference element in a tuple");}
258
259    template <class _Tp,
260              class = __enable_if_t<
261                  _And<
262                      _IsNotSame<__uncvref_t<_Tp>, __tuple_leaf>,
263                      is_constructible<_Hp, _Tp>
264                    >::value
265                >
266            >
267        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
268        explicit __tuple_leaf(_Tp&& __t) _NOEXCEPT_((is_nothrow_constructible<_Hp, _Tp>::value))
269            : __value_(_VSTD::forward<_Tp>(__t))
270        {static_assert(__can_bind_reference<_Tp&&>(),
271       "Attempted construction of reference element binds to a temporary whose lifetime has ended");}
272
273    template <class _Tp, class _Alloc>
274        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
275        explicit __tuple_leaf(integral_constant<int, 0>, const _Alloc&, _Tp&& __t)
276            : __value_(_VSTD::forward<_Tp>(__t))
277        {static_assert(__can_bind_reference<_Tp&&>(),
278       "Attempted construction of reference element binds to a temporary whose lifetime has ended");}
279
280    template <class _Tp, class _Alloc>
281        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
282        explicit __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a, _Tp&& __t)
283            : __value_(allocator_arg_t(), __a, _VSTD::forward<_Tp>(__t))
284        {static_assert(!is_reference<_Hp>::value,
285            "Attempted to uses-allocator construct a reference element in a tuple");}
286
287    template <class _Tp, class _Alloc>
288        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
289        explicit __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a, _Tp&& __t)
290            : __value_(_VSTD::forward<_Tp>(__t), __a)
291        {static_assert(!is_reference<_Hp>::value,
292           "Attempted to uses-allocator construct a reference element in a tuple");}
293
294    __tuple_leaf(const __tuple_leaf& __t) = default;
295    __tuple_leaf(__tuple_leaf&& __t) = default;
296
297    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
298    int swap(__tuple_leaf& __t) _NOEXCEPT_(__is_nothrow_swappable<__tuple_leaf>::value)
299    {
300        _VSTD::swap(*this, __t);
301        return 0;
302    }
303
304    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11       _Hp& get()       _NOEXCEPT {return __value_;}
305    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 const _Hp& get() const _NOEXCEPT {return __value_;}
306};
307
308template <size_t _Ip, class _Hp>
309class __tuple_leaf<_Ip, _Hp, true>
310    : private _Hp
311{
312    _LIBCPP_CONSTEXPR_AFTER_CXX11
313    __tuple_leaf& operator=(const __tuple_leaf&);
314public:
315    _LIBCPP_INLINE_VISIBILITY constexpr __tuple_leaf()
316             _NOEXCEPT_(is_nothrow_default_constructible<_Hp>::value) {}
317
318    template <class _Alloc>
319        _LIBCPP_INLINE_VISIBILITY constexpr
320        __tuple_leaf(integral_constant<int, 0>, const _Alloc&) {}
321
322    template <class _Alloc>
323        _LIBCPP_INLINE_VISIBILITY constexpr
324        __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a)
325            : _Hp(allocator_arg_t(), __a) {}
326
327    template <class _Alloc>
328        _LIBCPP_INLINE_VISIBILITY constexpr
329        __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a)
330            : _Hp(__a) {}
331
332    template <class _Tp,
333              class = __enable_if_t<
334                  _And<
335                    _IsNotSame<__uncvref_t<_Tp>, __tuple_leaf>,
336                    is_constructible<_Hp, _Tp>
337                  >::value
338                >
339            >
340        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
341        explicit __tuple_leaf(_Tp&& __t) _NOEXCEPT_((is_nothrow_constructible<_Hp, _Tp>::value))
342            : _Hp(_VSTD::forward<_Tp>(__t)) {}
343
344    template <class _Tp, class _Alloc>
345        _LIBCPP_INLINE_VISIBILITY constexpr
346        explicit __tuple_leaf(integral_constant<int, 0>, const _Alloc&, _Tp&& __t)
347            : _Hp(_VSTD::forward<_Tp>(__t)) {}
348
349    template <class _Tp, class _Alloc>
350        _LIBCPP_INLINE_VISIBILITY constexpr
351        explicit __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a, _Tp&& __t)
352            : _Hp(allocator_arg_t(), __a, _VSTD::forward<_Tp>(__t)) {}
353
354    template <class _Tp, class _Alloc>
355        _LIBCPP_INLINE_VISIBILITY constexpr
356        explicit __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a, _Tp&& __t)
357            : _Hp(_VSTD::forward<_Tp>(__t), __a) {}
358
359    __tuple_leaf(__tuple_leaf const &) = default;
360    __tuple_leaf(__tuple_leaf &&) = default;
361
362    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
363    int
364    swap(__tuple_leaf& __t) _NOEXCEPT_(__is_nothrow_swappable<__tuple_leaf>::value)
365    {
366        _VSTD::swap(*this, __t);
367        return 0;
368    }
369
370    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11       _Hp& get()       _NOEXCEPT {return static_cast<_Hp&>(*this);}
371    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 const _Hp& get() const _NOEXCEPT {return static_cast<const _Hp&>(*this);}
372};
373
374template <class ..._Tp>
375_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
376void __swallow(_Tp&&...) _NOEXCEPT {}
377
378template <class _Tp>
379struct __all_default_constructible;
380
381template <class ..._Tp>
382struct __all_default_constructible<__tuple_types<_Tp...>>
383    : __all<is_default_constructible<_Tp>::value...>
384{ };
385
386// __tuple_impl
387
388template<class _Indx, class ..._Tp> struct __tuple_impl;
389
390template<size_t ..._Indx, class ..._Tp>
391struct _LIBCPP_DECLSPEC_EMPTY_BASES __tuple_impl<__tuple_indices<_Indx...>, _Tp...>
392    : public __tuple_leaf<_Indx, _Tp>...
393{
394    _LIBCPP_INLINE_VISIBILITY
395    constexpr __tuple_impl()
396        _NOEXCEPT_(__all<is_nothrow_default_constructible<_Tp>::value...>::value) {}
397
398    template <size_t ..._Uf, class ..._Tf,
399              size_t ..._Ul, class ..._Tl, class ..._Up>
400        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
401        explicit
402        __tuple_impl(__tuple_indices<_Uf...>, __tuple_types<_Tf...>,
403                     __tuple_indices<_Ul...>, __tuple_types<_Tl...>,
404                     _Up&&... __u)
405                     _NOEXCEPT_((__all<is_nothrow_constructible<_Tf, _Up>::value...>::value &&
406                                 __all<is_nothrow_default_constructible<_Tl>::value...>::value)) :
407            __tuple_leaf<_Uf, _Tf>(_VSTD::forward<_Up>(__u))...,
408            __tuple_leaf<_Ul, _Tl>()...
409            {}
410
411    template <class _Alloc, size_t ..._Uf, class ..._Tf,
412              size_t ..._Ul, class ..._Tl, class ..._Up>
413        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
414        explicit
415        __tuple_impl(allocator_arg_t, const _Alloc& __a,
416                     __tuple_indices<_Uf...>, __tuple_types<_Tf...>,
417                     __tuple_indices<_Ul...>, __tuple_types<_Tl...>,
418                     _Up&&... __u) :
419            __tuple_leaf<_Uf, _Tf>(__uses_alloc_ctor<_Tf, _Alloc, _Up>(), __a,
420            _VSTD::forward<_Up>(__u))...,
421            __tuple_leaf<_Ul, _Tl>(__uses_alloc_ctor<_Tl, _Alloc>(), __a)...
422            {}
423
424    template <class _Tuple,
425              class = typename enable_if
426                      <
427                         __tuple_constructible<_Tuple, tuple<_Tp...> >::value
428                      >::type
429             >
430        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
431        __tuple_impl(_Tuple&& __t) _NOEXCEPT_((__all<is_nothrow_constructible<_Tp, typename tuple_element<_Indx,
432                                       typename __make_tuple_types<_Tuple>::type>::type>::value...>::value))
433            : __tuple_leaf<_Indx, _Tp>(_VSTD::forward<typename tuple_element<_Indx,
434                                       typename __make_tuple_types<_Tuple>::type>::type>(_VSTD::get<_Indx>(__t)))...
435            {}
436
437    template <class _Alloc, class _Tuple,
438              class = typename enable_if
439                      <
440                         __tuple_constructible<_Tuple, tuple<_Tp...> >::value
441                      >::type
442             >
443        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
444        __tuple_impl(allocator_arg_t, const _Alloc& __a, _Tuple&& __t)
445            : __tuple_leaf<_Indx, _Tp>(__uses_alloc_ctor<_Tp, _Alloc, typename tuple_element<_Indx,
446                                       typename __make_tuple_types<_Tuple>::type>::type>(), __a,
447                                       _VSTD::forward<typename tuple_element<_Indx,
448                                       typename __make_tuple_types<_Tuple>::type>::type>(_VSTD::get<_Indx>(__t)))...
449            {}
450
451    __tuple_impl(const __tuple_impl&) = default;
452    __tuple_impl(__tuple_impl&&) = default;
453
454    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
455    void swap(__tuple_impl& __t)
456        _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value)
457    {
458        _VSTD::__swallow(__tuple_leaf<_Indx, _Tp>::swap(static_cast<__tuple_leaf<_Indx, _Tp>&>(__t))...);
459    }
460};
461
462template<class _Dest, class _Source, size_t ..._Np>
463_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
464void __memberwise_copy_assign(_Dest& __dest, _Source const& __source, __tuple_indices<_Np...>) {
465    _VSTD::__swallow(((_VSTD::get<_Np>(__dest) = _VSTD::get<_Np>(__source)), void(), 0)...);
466}
467
468template<class _Dest, class _Source, class ..._Up, size_t ..._Np>
469_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
470void __memberwise_forward_assign(_Dest& __dest, _Source&& __source, __tuple_types<_Up...>, __tuple_indices<_Np...>) {
471    _VSTD::__swallow(((
472        _VSTD::get<_Np>(__dest) = _VSTD::forward<_Up>(_VSTD::get<_Np>(__source))
473    ), void(), 0)...);
474}
475
476template <class ..._Tp>
477class _LIBCPP_TEMPLATE_VIS tuple
478{
479    typedef __tuple_impl<typename __make_tuple_indices<sizeof...(_Tp)>::type, _Tp...> _BaseT;
480
481    _BaseT __base_;
482
483    template <size_t _Jp, class ..._Up> friend _LIBCPP_CONSTEXPR_AFTER_CXX11
484        typename tuple_element<_Jp, tuple<_Up...> >::type& get(tuple<_Up...>&) _NOEXCEPT;
485    template <size_t _Jp, class ..._Up> friend _LIBCPP_CONSTEXPR_AFTER_CXX11
486        const typename tuple_element<_Jp, tuple<_Up...> >::type& get(const tuple<_Up...>&) _NOEXCEPT;
487    template <size_t _Jp, class ..._Up> friend _LIBCPP_CONSTEXPR_AFTER_CXX11
488        typename tuple_element<_Jp, tuple<_Up...> >::type&& get(tuple<_Up...>&&) _NOEXCEPT;
489    template <size_t _Jp, class ..._Up> friend _LIBCPP_CONSTEXPR_AFTER_CXX11
490        const typename tuple_element<_Jp, tuple<_Up...> >::type&& get(const tuple<_Up...>&&) _NOEXCEPT;
491public:
492    // [tuple.cnstr]
493
494    // tuple() constructors (including allocator_arg_t variants)
495    template <template<class...> class _IsImpDefault = __is_implicitly_default_constructible, __enable_if_t<
496        _And<
497            _IsImpDefault<_Tp>... // explicit check
498        >::value
499    , int> = 0>
500    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
501    tuple()
502        _NOEXCEPT_(_And<is_nothrow_default_constructible<_Tp>...>::value)
503    { }
504
505    template <template<class...> class _IsImpDefault = __is_implicitly_default_constructible,
506              template<class...> class _IsDefault = is_default_constructible, __enable_if_t<
507        _And<
508            _IsDefault<_Tp>...,
509            _Not<_Lazy<_And, _IsImpDefault<_Tp>...> > // explicit check
510        >::value
511    , int> = 0>
512    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
513    explicit tuple()
514        _NOEXCEPT_(_And<is_nothrow_default_constructible<_Tp>...>::value)
515    { }
516
517    template <class _Alloc, template<class...> class _IsImpDefault = __is_implicitly_default_constructible, __enable_if_t<
518        _And<
519            _IsImpDefault<_Tp>... // explicit check
520        >::value
521    , int> = 0>
522    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
523    tuple(allocator_arg_t, _Alloc const& __a)
524      : __base_(allocator_arg_t(), __a,
525                    __tuple_indices<>(), __tuple_types<>(),
526                    typename __make_tuple_indices<sizeof...(_Tp), 0>::type(),
527                    __tuple_types<_Tp...>()) {}
528
529    template <class _Alloc,
530              template<class...> class _IsImpDefault = __is_implicitly_default_constructible,
531              template<class...> class _IsDefault = is_default_constructible, __enable_if_t<
532        _And<
533            _IsDefault<_Tp>...,
534            _Not<_Lazy<_And, _IsImpDefault<_Tp>...> > // explicit check
535        >::value
536    , int> = 0>
537    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
538    explicit tuple(allocator_arg_t, _Alloc const& __a)
539      : __base_(allocator_arg_t(), __a,
540                    __tuple_indices<>(), __tuple_types<>(),
541                    typename __make_tuple_indices<sizeof...(_Tp), 0>::type(),
542                    __tuple_types<_Tp...>()) {}
543
544    // tuple(const T&...) constructors (including allocator_arg_t variants)
545    template <template<class...> class _And = _And, __enable_if_t<
546        _And<
547            _BoolConstant<sizeof...(_Tp) >= 1>,
548            is_copy_constructible<_Tp>...,
549            is_convertible<const _Tp&, _Tp>... // explicit check
550        >::value
551    , int> = 0>
552    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
553    tuple(const _Tp& ... __t)
554        _NOEXCEPT_(_And<is_nothrow_copy_constructible<_Tp>...>::value)
555        : __base_(typename __make_tuple_indices<sizeof...(_Tp)>::type(),
556                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
557                typename __make_tuple_indices<0>::type(),
558                typename __make_tuple_types<tuple, 0>::type(),
559                __t...
560               ) {}
561
562    template <template<class...> class _And = _And, __enable_if_t<
563        _And<
564            _BoolConstant<sizeof...(_Tp) >= 1>,
565            is_copy_constructible<_Tp>...,
566            _Not<_Lazy<_And, is_convertible<const _Tp&, _Tp>...> > // explicit check
567        >::value
568    , int> = 0>
569    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
570    explicit tuple(const _Tp& ... __t)
571        _NOEXCEPT_(_And<is_nothrow_copy_constructible<_Tp>...>::value)
572        : __base_(typename __make_tuple_indices<sizeof...(_Tp)>::type(),
573                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
574                typename __make_tuple_indices<0>::type(),
575                typename __make_tuple_types<tuple, 0>::type(),
576                __t...
577               ) {}
578
579    template <class _Alloc, template<class...> class _And = _And, __enable_if_t<
580        _And<
581            _BoolConstant<sizeof...(_Tp) >= 1>,
582            is_copy_constructible<_Tp>...,
583            is_convertible<const _Tp&, _Tp>... // explicit check
584        >::value
585    , int> = 0>
586    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
587    tuple(allocator_arg_t, const _Alloc& __a, const _Tp& ... __t)
588        : __base_(allocator_arg_t(), __a,
589                typename __make_tuple_indices<sizeof...(_Tp)>::type(),
590                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
591                typename __make_tuple_indices<0>::type(),
592                typename __make_tuple_types<tuple, 0>::type(),
593                __t...
594               ) {}
595
596    template <class _Alloc, template<class...> class _And = _And, __enable_if_t<
597        _And<
598            _BoolConstant<sizeof...(_Tp) >= 1>,
599            is_copy_constructible<_Tp>...,
600            _Not<_Lazy<_And, is_convertible<const _Tp&, _Tp>...> > // explicit check
601        >::value
602    , int> = 0>
603    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
604    explicit tuple(allocator_arg_t, const _Alloc& __a, const _Tp& ... __t)
605        : __base_(allocator_arg_t(), __a,
606                typename __make_tuple_indices<sizeof...(_Tp)>::type(),
607                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
608                typename __make_tuple_indices<0>::type(),
609                typename __make_tuple_types<tuple, 0>::type(),
610                __t...
611               ) {}
612
613    // tuple(U&& ...) constructors (including allocator_arg_t variants)
614    template <class ..._Up> struct _IsThisTuple : false_type { };
615    template <class _Up> struct _IsThisTuple<_Up> : is_same<__uncvref_t<_Up>, tuple> { };
616
617    template <class ..._Up>
618    struct _EnableUTypesCtor : _And<
619        _BoolConstant<sizeof...(_Tp) >= 1>,
620        _Not<_IsThisTuple<_Up...> >, // extension to allow mis-behaved user constructors
621        is_constructible<_Tp, _Up>...
622    > { };
623
624    template <class ..._Up, __enable_if_t<
625        _And<
626            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
627            _EnableUTypesCtor<_Up...>,
628            is_convertible<_Up, _Tp>... // explicit check
629        >::value
630    , int> = 0>
631    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
632    tuple(_Up&&... __u)
633        _NOEXCEPT_((_And<is_nothrow_constructible<_Tp, _Up>...>::value))
634        : __base_(typename __make_tuple_indices<sizeof...(_Up)>::type(),
635                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
636                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
637                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
638                    _VSTD::forward<_Up>(__u)...) {}
639
640    template <class ..._Up, __enable_if_t<
641        _And<
642            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
643            _EnableUTypesCtor<_Up...>,
644            _Not<_Lazy<_And, is_convertible<_Up, _Tp>...> > // explicit check
645        >::value
646    , int> = 0>
647    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
648    explicit tuple(_Up&&... __u)
649        _NOEXCEPT_((_And<is_nothrow_constructible<_Tp, _Up>...>::value))
650        : __base_(typename __make_tuple_indices<sizeof...(_Up)>::type(),
651                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
652                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
653                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
654                    _VSTD::forward<_Up>(__u)...) {}
655
656    template <class _Alloc, class ..._Up, __enable_if_t<
657        _And<
658            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
659            _EnableUTypesCtor<_Up...>,
660            is_convertible<_Up, _Tp>... // explicit check
661        >::value
662    , int> = 0>
663    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
664    tuple(allocator_arg_t, const _Alloc& __a, _Up&&... __u)
665        : __base_(allocator_arg_t(), __a,
666                    typename __make_tuple_indices<sizeof...(_Up)>::type(),
667                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
668                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
669                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
670                    _VSTD::forward<_Up>(__u)...) {}
671
672    template <class _Alloc, class ..._Up, __enable_if_t<
673        _And<
674            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
675            _EnableUTypesCtor<_Up...>,
676            _Not<_Lazy<_And, is_convertible<_Up, _Tp>...> > // explicit check
677        >::value
678    , int> = 0>
679    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
680    explicit tuple(allocator_arg_t, const _Alloc& __a, _Up&&... __u)
681        : __base_(allocator_arg_t(), __a,
682                    typename __make_tuple_indices<sizeof...(_Up)>::type(),
683                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
684                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
685                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
686                    _VSTD::forward<_Up>(__u)...) {}
687
688    // Copy and move constructors (including the allocator_arg_t variants)
689    tuple(const tuple&) = default;
690    tuple(tuple&&) = default;
691
692    template <class _Alloc, template<class...> class _And = _And, __enable_if_t<
693        _And<is_copy_constructible<_Tp>...>::value
694    , int> = 0>
695    tuple(allocator_arg_t, const _Alloc& __alloc, const tuple& __t)
696        : __base_(allocator_arg_t(), __alloc, __t)
697    { }
698
699    template <class _Alloc, template<class...> class _And = _And, __enable_if_t<
700        _And<is_move_constructible<_Tp>...>::value
701    , int> = 0>
702    tuple(allocator_arg_t, const _Alloc& __alloc, tuple&& __t)
703        : __base_(allocator_arg_t(), __alloc, _VSTD::move(__t))
704    { }
705
706    // tuple(const tuple<U...>&) constructors (including allocator_arg_t variants)
707    template <class ..._Up>
708    struct _EnableCopyFromOtherTuple : _And<
709        _Not<is_same<tuple<_Tp...>, tuple<_Up...> > >,
710        _Lazy<_Or,
711            _BoolConstant<sizeof...(_Tp) != 1>,
712            // _Tp and _Up are 1-element packs - the pack expansions look
713            // weird to avoid tripping up the type traits in degenerate cases
714            _Lazy<_And,
715                _Not<is_convertible<const tuple<_Up>&, _Tp> >...,
716                _Not<is_constructible<_Tp, const tuple<_Up>&> >...
717            >
718        >,
719        is_constructible<_Tp, const _Up&>...
720    > { };
721
722    template <class ..._Up, __enable_if_t<
723        _And<
724            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
725            _EnableCopyFromOtherTuple<_Up...>,
726            is_convertible<const _Up&, _Tp>... // explicit check
727        >::value
728    , int> = 0>
729    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
730    tuple(const tuple<_Up...>& __t)
731        _NOEXCEPT_((_And<is_nothrow_constructible<_Tp, const _Up&>...>::value))
732        : __base_(__t)
733    { }
734
735    template <class ..._Up, __enable_if_t<
736        _And<
737            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
738            _EnableCopyFromOtherTuple<_Up...>,
739            _Not<_Lazy<_And, is_convertible<const _Up&, _Tp>...> > // explicit check
740        >::value
741    , int> = 0>
742    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
743    explicit tuple(const tuple<_Up...>& __t)
744        _NOEXCEPT_((_And<is_nothrow_constructible<_Tp, const _Up&>...>::value))
745        : __base_(__t)
746    { }
747
748    template <class ..._Up, class _Alloc, __enable_if_t<
749        _And<
750            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
751            _EnableCopyFromOtherTuple<_Up...>,
752            is_convertible<const _Up&, _Tp>... // explicit check
753        >::value
754    , int> = 0>
755    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
756    tuple(allocator_arg_t, const _Alloc& __a, const tuple<_Up...>& __t)
757        : __base_(allocator_arg_t(), __a, __t)
758    { }
759
760    template <class ..._Up, class _Alloc, __enable_if_t<
761        _And<
762            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
763            _EnableCopyFromOtherTuple<_Up...>,
764            _Not<_Lazy<_And, is_convertible<const _Up&, _Tp>...> > // explicit check
765        >::value
766    , int> = 0>
767    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
768    explicit tuple(allocator_arg_t, const _Alloc& __a, const tuple<_Up...>& __t)
769        : __base_(allocator_arg_t(), __a, __t)
770    { }
771
772    // tuple(tuple<U...>&&) constructors (including allocator_arg_t variants)
773    template <class ..._Up>
774    struct _EnableMoveFromOtherTuple : _And<
775        _Not<is_same<tuple<_Tp...>, tuple<_Up...> > >,
776        _Lazy<_Or,
777            _BoolConstant<sizeof...(_Tp) != 1>,
778            // _Tp and _Up are 1-element packs - the pack expansions look
779            // weird to avoid tripping up the type traits in degenerate cases
780            _Lazy<_And,
781                _Not<is_convertible<tuple<_Up>, _Tp> >...,
782                _Not<is_constructible<_Tp, tuple<_Up> > >...
783            >
784        >,
785        is_constructible<_Tp, _Up>...
786    > { };
787
788    template <class ..._Up, __enable_if_t<
789        _And<
790            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
791            _EnableMoveFromOtherTuple<_Up...>,
792            is_convertible<_Up, _Tp>... // explicit check
793        >::value
794    , int> = 0>
795    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
796    tuple(tuple<_Up...>&& __t)
797        _NOEXCEPT_((_And<is_nothrow_constructible<_Tp, _Up>...>::value))
798        : __base_(_VSTD::move(__t))
799    { }
800
801    template <class ..._Up, __enable_if_t<
802        _And<
803            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
804            _EnableMoveFromOtherTuple<_Up...>,
805            _Not<_Lazy<_And, is_convertible<_Up, _Tp>...> > // explicit check
806        >::value
807    , int> = 0>
808    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
809    explicit tuple(tuple<_Up...>&& __t)
810        _NOEXCEPT_((_And<is_nothrow_constructible<_Tp, _Up>...>::value))
811        : __base_(_VSTD::move(__t))
812    { }
813
814    template <class _Alloc, class ..._Up, __enable_if_t<
815        _And<
816            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
817            _EnableMoveFromOtherTuple<_Up...>,
818            is_convertible<_Up, _Tp>... // explicit check
819        >::value
820    , int> = 0>
821    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
822    tuple(allocator_arg_t, const _Alloc& __a, tuple<_Up...>&& __t)
823        : __base_(allocator_arg_t(), __a, _VSTD::move(__t))
824    { }
825
826    template <class _Alloc, class ..._Up, __enable_if_t<
827        _And<
828            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
829            _EnableMoveFromOtherTuple<_Up...>,
830            _Not<_Lazy<_And, is_convertible<_Up, _Tp>...> > // explicit check
831        >::value
832    , int> = 0>
833    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
834    explicit tuple(allocator_arg_t, const _Alloc& __a, tuple<_Up...>&& __t)
835        : __base_(allocator_arg_t(), __a, _VSTD::move(__t))
836    { }
837
838    // tuple(const pair<U1, U2>&) constructors (including allocator_arg_t variants)
839    template <class _Up1, class _Up2, class ..._DependentTp>
840    struct _EnableImplicitCopyFromPair : _And<
841        is_constructible<_FirstType<_DependentTp...>, const _Up1&>,
842        is_constructible<_SecondType<_DependentTp...>, const _Up2&>,
843        is_convertible<const _Up1&, _FirstType<_DependentTp...> >, // explicit check
844        is_convertible<const _Up2&, _SecondType<_DependentTp...> >
845    > { };
846
847    template <class _Up1, class _Up2, class ..._DependentTp>
848    struct _EnableExplicitCopyFromPair : _And<
849        is_constructible<_FirstType<_DependentTp...>, const _Up1&>,
850        is_constructible<_SecondType<_DependentTp...>, const _Up2&>,
851        _Not<is_convertible<const _Up1&, _FirstType<_DependentTp...> > >, // explicit check
852        _Not<is_convertible<const _Up2&, _SecondType<_DependentTp...> > >
853    > { };
854
855    template <class _Up1, class _Up2, template<class...> class _And = _And, __enable_if_t<
856        _And<
857            _BoolConstant<sizeof...(_Tp) == 2>,
858            _EnableImplicitCopyFromPair<_Up1, _Up2, _Tp...>
859        >::value
860    , int> = 0>
861    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
862    tuple(const pair<_Up1, _Up2>& __p)
863        _NOEXCEPT_((_And<
864            is_nothrow_constructible<_FirstType<_Tp...>, const _Up1&>,
865            is_nothrow_constructible<_SecondType<_Tp...>, const _Up2&>
866        >::value))
867        : __base_(__p)
868    { }
869
870    template <class _Up1, class _Up2, template<class...> class _And = _And, __enable_if_t<
871        _And<
872            _BoolConstant<sizeof...(_Tp) == 2>,
873            _EnableExplicitCopyFromPair<_Up1, _Up2, _Tp...>
874        >::value
875    , int> = 0>
876    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
877    explicit tuple(const pair<_Up1, _Up2>& __p)
878        _NOEXCEPT_((_And<
879            is_nothrow_constructible<_FirstType<_Tp...>, const _Up1&>,
880            is_nothrow_constructible<_SecondType<_Tp...>, const _Up2&>
881        >::value))
882        : __base_(__p)
883    { }
884
885    template <class _Alloc, class _Up1, class _Up2, template<class...> class _And = _And, __enable_if_t<
886        _And<
887            _BoolConstant<sizeof...(_Tp) == 2>,
888            _EnableImplicitCopyFromPair<_Up1, _Up2, _Tp...>
889        >::value
890    , int> = 0>
891    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
892    tuple(allocator_arg_t, const _Alloc& __a, const pair<_Up1, _Up2>& __p)
893        : __base_(allocator_arg_t(), __a, __p)
894    { }
895
896    template <class _Alloc, class _Up1, class _Up2, template<class...> class _And = _And, __enable_if_t<
897        _And<
898            _BoolConstant<sizeof...(_Tp) == 2>,
899            _EnableExplicitCopyFromPair<_Up1, _Up2, _Tp...>
900        >::value
901    , int> = 0>
902    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
903    explicit tuple(allocator_arg_t, const _Alloc& __a, const pair<_Up1, _Up2>& __p)
904        : __base_(allocator_arg_t(), __a, __p)
905    { }
906
907    // tuple(pair<U1, U2>&&) constructors (including allocator_arg_t variants)
908    template <class _Up1, class _Up2, class ..._DependentTp>
909    struct _EnableImplicitMoveFromPair : _And<
910        is_constructible<_FirstType<_DependentTp...>, _Up1>,
911        is_constructible<_SecondType<_DependentTp...>, _Up2>,
912        is_convertible<_Up1, _FirstType<_DependentTp...> >, // explicit check
913        is_convertible<_Up2, _SecondType<_DependentTp...> >
914    > { };
915
916    template <class _Up1, class _Up2, class ..._DependentTp>
917    struct _EnableExplicitMoveFromPair : _And<
918        is_constructible<_FirstType<_DependentTp...>, _Up1>,
919        is_constructible<_SecondType<_DependentTp...>, _Up2>,
920        _Not<is_convertible<_Up1, _FirstType<_DependentTp...> > >, // explicit check
921        _Not<is_convertible<_Up2, _SecondType<_DependentTp...> > >
922    > { };
923
924    template <class _Up1, class _Up2, template<class...> class _And = _And, __enable_if_t<
925        _And<
926            _BoolConstant<sizeof...(_Tp) == 2>,
927            _EnableImplicitMoveFromPair<_Up1, _Up2, _Tp...>
928        >::value
929    , int> = 0>
930    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
931    tuple(pair<_Up1, _Up2>&& __p)
932        _NOEXCEPT_((_And<
933            is_nothrow_constructible<_FirstType<_Tp...>, _Up1>,
934            is_nothrow_constructible<_SecondType<_Tp...>, _Up2>
935        >::value))
936        : __base_(_VSTD::move(__p))
937    { }
938
939    template <class _Up1, class _Up2, template<class...> class _And = _And, __enable_if_t<
940        _And<
941            _BoolConstant<sizeof...(_Tp) == 2>,
942            _EnableExplicitMoveFromPair<_Up1, _Up2, _Tp...>
943        >::value
944    , int> = 0>
945    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
946    explicit tuple(pair<_Up1, _Up2>&& __p)
947        _NOEXCEPT_((_And<
948            is_nothrow_constructible<_FirstType<_Tp...>, _Up1>,
949            is_nothrow_constructible<_SecondType<_Tp...>, _Up2>
950        >::value))
951        : __base_(_VSTD::move(__p))
952    { }
953
954    template <class _Alloc, class _Up1, class _Up2, template<class...> class _And = _And, __enable_if_t<
955        _And<
956            _BoolConstant<sizeof...(_Tp) == 2>,
957            _EnableImplicitMoveFromPair<_Up1, _Up2, _Tp...>
958        >::value
959    , int> = 0>
960    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
961    tuple(allocator_arg_t, const _Alloc& __a, pair<_Up1, _Up2>&& __p)
962        : __base_(allocator_arg_t(), __a, _VSTD::move(__p))
963    { }
964
965    template <class _Alloc, class _Up1, class _Up2, template<class...> class _And = _And, __enable_if_t<
966        _And<
967            _BoolConstant<sizeof...(_Tp) == 2>,
968            _EnableExplicitMoveFromPair<_Up1, _Up2, _Tp...>
969        >::value
970    , int> = 0>
971    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
972    explicit tuple(allocator_arg_t, const _Alloc& __a, pair<_Up1, _Up2>&& __p)
973        : __base_(allocator_arg_t(), __a, _VSTD::move(__p))
974    { }
975
976    // [tuple.assign]
977    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
978    tuple& operator=(_If<_And<is_copy_assignable<_Tp>...>::value, tuple, __nat> const& __tuple)
979        _NOEXCEPT_((_And<is_nothrow_copy_assignable<_Tp>...>::value))
980    {
981        _VSTD::__memberwise_copy_assign(*this, __tuple,
982            typename __make_tuple_indices<sizeof...(_Tp)>::type());
983        return *this;
984    }
985
986    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
987    tuple& operator=(_If<_And<is_move_assignable<_Tp>...>::value, tuple, __nat>&& __tuple)
988        _NOEXCEPT_((_And<is_nothrow_move_assignable<_Tp>...>::value))
989    {
990        _VSTD::__memberwise_forward_assign(*this, _VSTD::move(__tuple),
991            __tuple_types<_Tp...>(),
992            typename __make_tuple_indices<sizeof...(_Tp)>::type());
993        return *this;
994    }
995
996    template<class... _Up, __enable_if_t<
997        _And<
998            _BoolConstant<sizeof...(_Tp) == sizeof...(_Up)>,
999            is_assignable<_Tp&, _Up const&>...
1000        >::value
1001    ,int> = 0>
1002    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
1003    tuple& operator=(tuple<_Up...> const& __tuple)
1004        _NOEXCEPT_((_And<is_nothrow_assignable<_Tp&, _Up const&>...>::value))
1005    {
1006        _VSTD::__memberwise_copy_assign(*this, __tuple,
1007            typename __make_tuple_indices<sizeof...(_Tp)>::type());
1008        return *this;
1009    }
1010
1011    template<class... _Up, __enable_if_t<
1012        _And<
1013            _BoolConstant<sizeof...(_Tp) == sizeof...(_Up)>,
1014            is_assignable<_Tp&, _Up>...
1015        >::value
1016    ,int> = 0>
1017    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
1018    tuple& operator=(tuple<_Up...>&& __tuple)
1019        _NOEXCEPT_((_And<is_nothrow_assignable<_Tp&, _Up>...>::value))
1020    {
1021        _VSTD::__memberwise_forward_assign(*this, _VSTD::move(__tuple),
1022            __tuple_types<_Up...>(),
1023            typename __make_tuple_indices<sizeof...(_Tp)>::type());
1024        return *this;
1025    }
1026
1027    template<class _Up1, class _Up2, class _Dep = true_type, __enable_if_t<
1028        _And<_Dep,
1029            _BoolConstant<sizeof...(_Tp) == 2>,
1030            is_assignable<_FirstType<_Tp..., _Dep>&, _Up1 const&>,
1031            is_assignable<_SecondType<_Tp..., _Dep>&, _Up2 const&>
1032        >::value
1033    ,int> = 0>
1034    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
1035    tuple& operator=(pair<_Up1, _Up2> const& __pair)
1036        _NOEXCEPT_((_And<
1037            is_nothrow_assignable<_FirstType<_Tp...>&, _Up1 const&>,
1038            is_nothrow_assignable<_SecondType<_Tp...>&, _Up2 const&>
1039        >::value))
1040    {
1041        _VSTD::get<0>(*this) = __pair.first;
1042        _VSTD::get<1>(*this) = __pair.second;
1043        return *this;
1044    }
1045
1046    template<class _Up1, class _Up2, class _Dep = true_type, __enable_if_t<
1047        _And<_Dep,
1048            _BoolConstant<sizeof...(_Tp) == 2>,
1049            is_assignable<_FirstType<_Tp..., _Dep>&, _Up1>,
1050            is_assignable<_SecondType<_Tp..., _Dep>&, _Up2>
1051        >::value
1052    ,int> = 0>
1053    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
1054    tuple& operator=(pair<_Up1, _Up2>&& __pair)
1055        _NOEXCEPT_((_And<
1056            is_nothrow_assignable<_FirstType<_Tp...>&, _Up1>,
1057            is_nothrow_assignable<_SecondType<_Tp...>&, _Up2>
1058        >::value))
1059    {
1060        _VSTD::get<0>(*this) = _VSTD::forward<_Up1>(__pair.first);
1061        _VSTD::get<1>(*this) = _VSTD::forward<_Up2>(__pair.second);
1062        return *this;
1063    }
1064
1065    // EXTENSION
1066    template<class _Up, size_t _Np, class = __enable_if_t<
1067        _And<
1068            _BoolConstant<_Np == sizeof...(_Tp)>,
1069            is_assignable<_Tp&, _Up const&>...
1070        >::value
1071    > >
1072    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
1073    tuple& operator=(array<_Up, _Np> const& __array)
1074        _NOEXCEPT_((_And<is_nothrow_assignable<_Tp&, _Up const&>...>::value))
1075    {
1076        _VSTD::__memberwise_copy_assign(*this, __array,
1077            typename __make_tuple_indices<sizeof...(_Tp)>::type());
1078        return *this;
1079    }
1080
1081    // EXTENSION
1082    template<class _Up, size_t _Np, class = void, class = __enable_if_t<
1083        _And<
1084            _BoolConstant<_Np == sizeof...(_Tp)>,
1085            is_assignable<_Tp&, _Up>...
1086        >::value
1087    > >
1088    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
1089    tuple& operator=(array<_Up, _Np>&& __array)
1090        _NOEXCEPT_((_And<is_nothrow_assignable<_Tp&, _Up>...>::value))
1091    {
1092        _VSTD::__memberwise_forward_assign(*this, _VSTD::move(__array),
1093            __tuple_types<_If<true, _Up, _Tp>...>(),
1094            typename __make_tuple_indices<sizeof...(_Tp)>::type());
1095        return *this;
1096    }
1097
1098    // [tuple.swap]
1099    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
1100    void swap(tuple& __t) _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value)
1101        {__base_.swap(__t.__base_);}
1102};
1103
1104template <>
1105class _LIBCPP_TEMPLATE_VIS tuple<>
1106{
1107public:
1108    _LIBCPP_INLINE_VISIBILITY constexpr
1109        tuple() _NOEXCEPT = default;
1110    template <class _Alloc>
1111    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
1112        tuple(allocator_arg_t, const _Alloc&) _NOEXCEPT {}
1113    template <class _Alloc>
1114    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
1115        tuple(allocator_arg_t, const _Alloc&, const tuple&) _NOEXCEPT {}
1116    template <class _Up>
1117    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
1118        tuple(array<_Up, 0>) _NOEXCEPT {}
1119    template <class _Alloc, class _Up>
1120    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
1121        tuple(allocator_arg_t, const _Alloc&, array<_Up, 0>) _NOEXCEPT {}
1122    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
1123    void swap(tuple&) _NOEXCEPT {}
1124};
1125
1126#if _LIBCPP_STD_VER > 20
1127template <class... _TTypes, class... _UTypes, template<class> class _TQual, template<class> class _UQual>
1128    requires requires { typename tuple<common_reference_t<_TQual<_TTypes>, _UQual<_UTypes>>...>; }
1129struct basic_common_reference<tuple<_TTypes...>, tuple<_UTypes...>, _TQual, _UQual> {
1130    using type = tuple<common_reference_t<_TQual<_TTypes>, _UQual<_UTypes>>...>;
1131};
1132
1133template <class... _TTypes, class... _UTypes>
1134    requires requires { typename tuple<common_type_t<_TTypes, _UTypes>...>; }
1135struct common_type<tuple<_TTypes...>, tuple<_UTypes...>> {
1136    using type = tuple<common_type_t<_TTypes, _UTypes>...>;
1137};
1138#endif // _LIBCPP_STD_VER > 20
1139
1140#if _LIBCPP_STD_VER > 14
1141template <class ..._Tp>
1142tuple(_Tp...) -> tuple<_Tp...>;
1143template <class _Tp1, class _Tp2>
1144tuple(pair<_Tp1, _Tp2>) -> tuple<_Tp1, _Tp2>;
1145template <class _Alloc, class ..._Tp>
1146tuple(allocator_arg_t, _Alloc, _Tp...) -> tuple<_Tp...>;
1147template <class _Alloc, class _Tp1, class _Tp2>
1148tuple(allocator_arg_t, _Alloc, pair<_Tp1, _Tp2>) -> tuple<_Tp1, _Tp2>;
1149template <class _Alloc, class ..._Tp>
1150tuple(allocator_arg_t, _Alloc, tuple<_Tp...>) -> tuple<_Tp...>;
1151#endif
1152
1153template <class ..._Tp>
1154inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
1155typename enable_if
1156<
1157    __all<__is_swappable<_Tp>::value...>::value,
1158    void
1159>::type
1160swap(tuple<_Tp...>& __t, tuple<_Tp...>& __u)
1161                 _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value)
1162    {__t.swap(__u);}
1163
1164// get
1165
1166template <size_t _Ip, class ..._Tp>
1167inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1168typename tuple_element<_Ip, tuple<_Tp...> >::type&
1169get(tuple<_Tp...>& __t) _NOEXCEPT
1170{
1171    typedef _LIBCPP_NODEBUG typename tuple_element<_Ip, tuple<_Tp...> >::type type;
1172    return static_cast<__tuple_leaf<_Ip, type>&>(__t.__base_).get();
1173}
1174
1175template <size_t _Ip, class ..._Tp>
1176inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1177const typename tuple_element<_Ip, tuple<_Tp...> >::type&
1178get(const tuple<_Tp...>& __t) _NOEXCEPT
1179{
1180    typedef _LIBCPP_NODEBUG typename tuple_element<_Ip, tuple<_Tp...> >::type type;
1181    return static_cast<const __tuple_leaf<_Ip, type>&>(__t.__base_).get();
1182}
1183
1184template <size_t _Ip, class ..._Tp>
1185inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1186typename tuple_element<_Ip, tuple<_Tp...> >::type&&
1187get(tuple<_Tp...>&& __t) _NOEXCEPT
1188{
1189    typedef _LIBCPP_NODEBUG typename tuple_element<_Ip, tuple<_Tp...> >::type type;
1190    return static_cast<type&&>(
1191             static_cast<__tuple_leaf<_Ip, type>&&>(__t.__base_).get());
1192}
1193
1194template <size_t _Ip, class ..._Tp>
1195inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1196const typename tuple_element<_Ip, tuple<_Tp...> >::type&&
1197get(const tuple<_Tp...>&& __t) _NOEXCEPT
1198{
1199    typedef _LIBCPP_NODEBUG typename tuple_element<_Ip, tuple<_Tp...> >::type type;
1200    return static_cast<const type&&>(
1201             static_cast<const __tuple_leaf<_Ip, type>&&>(__t.__base_).get());
1202}
1203
1204#if _LIBCPP_STD_VER > 11
1205
1206namespace __find_detail {
1207
1208static constexpr size_t __not_found = static_cast<size_t>(-1);
1209static constexpr size_t __ambiguous = __not_found - 1;
1210
1211inline _LIBCPP_INLINE_VISIBILITY
1212constexpr size_t __find_idx_return(size_t __curr_i, size_t __res, bool __matches) {
1213    return !__matches ? __res :
1214        (__res == __not_found ? __curr_i : __ambiguous);
1215}
1216
1217template <size_t _Nx>
1218inline _LIBCPP_INLINE_VISIBILITY
1219constexpr size_t __find_idx(size_t __i, const bool (&__matches)[_Nx]) {
1220  return __i == _Nx ? __not_found :
1221      __find_idx_return(__i, __find_idx(__i + 1, __matches), __matches[__i]);
1222}
1223
1224template <class _T1, class ..._Args>
1225struct __find_exactly_one_checked {
1226    static constexpr bool __matches[sizeof...(_Args)] = {is_same<_T1, _Args>::value...};
1227    static constexpr size_t value = __find_detail::__find_idx(0, __matches);
1228    static_assert(value != __not_found, "type not found in type list" );
1229    static_assert(value != __ambiguous, "type occurs more than once in type list");
1230};
1231
1232template <class _T1>
1233struct __find_exactly_one_checked<_T1> {
1234    static_assert(!is_same<_T1, _T1>::value, "type not in empty type list");
1235};
1236
1237} // namespace __find_detail
1238
1239template <typename _T1, typename... _Args>
1240struct __find_exactly_one_t
1241    : public __find_detail::__find_exactly_one_checked<_T1, _Args...> {
1242};
1243
1244template <class _T1, class... _Args>
1245inline _LIBCPP_INLINE_VISIBILITY
1246constexpr _T1& get(tuple<_Args...>& __tup) noexcept
1247{
1248    return _VSTD::get<__find_exactly_one_t<_T1, _Args...>::value>(__tup);
1249}
1250
1251template <class _T1, class... _Args>
1252inline _LIBCPP_INLINE_VISIBILITY
1253constexpr _T1 const& get(tuple<_Args...> const& __tup) noexcept
1254{
1255    return _VSTD::get<__find_exactly_one_t<_T1, _Args...>::value>(__tup);
1256}
1257
1258template <class _T1, class... _Args>
1259inline _LIBCPP_INLINE_VISIBILITY
1260constexpr _T1&& get(tuple<_Args...>&& __tup) noexcept
1261{
1262    return _VSTD::get<__find_exactly_one_t<_T1, _Args...>::value>(_VSTD::move(__tup));
1263}
1264
1265template <class _T1, class... _Args>
1266inline _LIBCPP_INLINE_VISIBILITY
1267constexpr _T1 const&& get(tuple<_Args...> const&& __tup) noexcept
1268{
1269    return _VSTD::get<__find_exactly_one_t<_T1, _Args...>::value>(_VSTD::move(__tup));
1270}
1271
1272#endif
1273
1274// tie
1275
1276template <class ..._Tp>
1277inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1278tuple<_Tp&...>
1279tie(_Tp&... __t) _NOEXCEPT
1280{
1281    return tuple<_Tp&...>(__t...);
1282}
1283
1284template <class _Up>
1285struct __ignore_t
1286{
1287    template <class _Tp>
1288    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1289    const __ignore_t& operator=(_Tp&&) const {return *this;}
1290};
1291
1292namespace {
1293  constexpr __ignore_t<unsigned char> ignore = __ignore_t<unsigned char>();
1294} // namespace
1295
1296template <class... _Tp>
1297inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1298tuple<typename __unwrap_ref_decay<_Tp>::type...>
1299make_tuple(_Tp&&... __t)
1300{
1301    return tuple<typename __unwrap_ref_decay<_Tp>::type...>(_VSTD::forward<_Tp>(__t)...);
1302}
1303
1304template <class... _Tp>
1305inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1306tuple<_Tp&&...>
1307forward_as_tuple(_Tp&&... __t) _NOEXCEPT
1308{
1309    return tuple<_Tp&&...>(_VSTD::forward<_Tp>(__t)...);
1310}
1311
1312template <size_t _Ip>
1313struct __tuple_equal
1314{
1315    template <class _Tp, class _Up>
1316    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1317    bool operator()(const _Tp& __x, const _Up& __y)
1318    {
1319        return __tuple_equal<_Ip - 1>()(__x, __y) && _VSTD::get<_Ip-1>(__x) == _VSTD::get<_Ip-1>(__y);
1320    }
1321};
1322
1323template <>
1324struct __tuple_equal<0>
1325{
1326    template <class _Tp, class _Up>
1327    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1328    bool operator()(const _Tp&, const _Up&)
1329    {
1330        return true;
1331    }
1332};
1333
1334template <class ..._Tp, class ..._Up>
1335inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1336bool
1337operator==(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1338{
1339    static_assert (sizeof...(_Tp) == sizeof...(_Up), "Can't compare tuples of different sizes");
1340    return __tuple_equal<sizeof...(_Tp)>()(__x, __y);
1341}
1342
1343#if _LIBCPP_STD_VER > 17
1344
1345// operator<=>
1346
1347template <class ..._Tp, class ..._Up, size_t ..._Is>
1348_LIBCPP_HIDE_FROM_ABI constexpr
1349auto
1350__tuple_compare_three_way(const tuple<_Tp...>& __x, const tuple<_Up...>& __y, index_sequence<_Is...>) {
1351    common_comparison_category_t<__synth_three_way_result<_Tp, _Up>...> __result = strong_ordering::equal;
1352    static_cast<void>(((__result = _VSTD::__synth_three_way(_VSTD::get<_Is>(__x), _VSTD::get<_Is>(__y)), __result != 0) || ...));
1353    return __result;
1354}
1355
1356template <class ..._Tp, class ..._Up>
1357requires (sizeof...(_Tp) == sizeof...(_Up))
1358_LIBCPP_HIDE_FROM_ABI constexpr
1359common_comparison_category_t<__synth_three_way_result<_Tp, _Up>...>
1360operator<=>(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1361{
1362    return _VSTD::__tuple_compare_three_way(__x, __y, index_sequence_for<_Tp...>{});
1363}
1364
1365#else // _LIBCPP_STD_VER > 17
1366
1367template <class ..._Tp, class ..._Up>
1368inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1369bool
1370operator!=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1371{
1372    return !(__x == __y);
1373}
1374
1375template <size_t _Ip>
1376struct __tuple_less
1377{
1378    template <class _Tp, class _Up>
1379    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1380    bool operator()(const _Tp& __x, const _Up& __y)
1381    {
1382        const size_t __idx = tuple_size<_Tp>::value - _Ip;
1383        if (_VSTD::get<__idx>(__x) < _VSTD::get<__idx>(__y))
1384            return true;
1385        if (_VSTD::get<__idx>(__y) < _VSTD::get<__idx>(__x))
1386            return false;
1387        return __tuple_less<_Ip-1>()(__x, __y);
1388    }
1389};
1390
1391template <>
1392struct __tuple_less<0>
1393{
1394    template <class _Tp, class _Up>
1395    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1396    bool operator()(const _Tp&, const _Up&)
1397    {
1398        return false;
1399    }
1400};
1401
1402template <class ..._Tp, class ..._Up>
1403inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1404bool
1405operator<(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1406{
1407    static_assert (sizeof...(_Tp) == sizeof...(_Up), "Can't compare tuples of different sizes");
1408    return __tuple_less<sizeof...(_Tp)>()(__x, __y);
1409}
1410
1411template <class ..._Tp, class ..._Up>
1412inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1413bool
1414operator>(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1415{
1416    return __y < __x;
1417}
1418
1419template <class ..._Tp, class ..._Up>
1420inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1421bool
1422operator>=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1423{
1424    return !(__x < __y);
1425}
1426
1427template <class ..._Tp, class ..._Up>
1428inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1429bool
1430operator<=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1431{
1432    return !(__y < __x);
1433}
1434
1435#endif // _LIBCPP_STD_VER > 17
1436
1437// tuple_cat
1438
1439template <class _Tp, class _Up> struct __tuple_cat_type;
1440
1441template <class ..._Ttypes, class ..._Utypes>
1442struct __tuple_cat_type<tuple<_Ttypes...>, __tuple_types<_Utypes...> >
1443{
1444    typedef _LIBCPP_NODEBUG tuple<_Ttypes..., _Utypes...> type;
1445};
1446
1447template <class _ResultTuple, bool _Is_Tuple0TupleLike, class ..._Tuples>
1448struct __tuple_cat_return_1
1449{
1450};
1451
1452template <class ..._Types, class _Tuple0>
1453struct __tuple_cat_return_1<tuple<_Types...>, true, _Tuple0>
1454{
1455  using type _LIBCPP_NODEBUG = typename __tuple_cat_type<
1456      tuple<_Types...>,
1457      typename __make_tuple_types<__uncvref_t<_Tuple0> >::type
1458    >::type;
1459};
1460
1461template <class ..._Types, class _Tuple0, class _Tuple1, class ..._Tuples>
1462struct __tuple_cat_return_1<tuple<_Types...>, true, _Tuple0, _Tuple1, _Tuples...>
1463    : public __tuple_cat_return_1<
1464                 typename __tuple_cat_type<
1465                     tuple<_Types...>,
1466                     typename __make_tuple_types<__uncvref_t<_Tuple0> >::type
1467                 >::type,
1468                 __tuple_like<typename remove_reference<_Tuple1>::type>::value,
1469                 _Tuple1, _Tuples...>
1470{
1471};
1472
1473template <class ..._Tuples> struct __tuple_cat_return;
1474
1475template <class _Tuple0, class ..._Tuples>
1476struct __tuple_cat_return<_Tuple0, _Tuples...>
1477    : public __tuple_cat_return_1<tuple<>,
1478         __tuple_like<typename remove_reference<_Tuple0>::type>::value, _Tuple0,
1479                                                                     _Tuples...>
1480{
1481};
1482
1483template <>
1484struct __tuple_cat_return<>
1485{
1486    typedef _LIBCPP_NODEBUG tuple<> type;
1487};
1488
1489inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1490tuple<>
1491tuple_cat()
1492{
1493    return tuple<>();
1494}
1495
1496template <class _Rp, class _Indices, class _Tuple0, class ..._Tuples>
1497struct __tuple_cat_return_ref_imp;
1498
1499template <class ..._Types, size_t ..._I0, class _Tuple0>
1500struct __tuple_cat_return_ref_imp<tuple<_Types...>, __tuple_indices<_I0...>, _Tuple0>
1501{
1502    typedef _LIBCPP_NODEBUG typename remove_reference<_Tuple0>::type _T0;
1503    typedef tuple<_Types..., typename __apply_cv<_Tuple0,
1504                          typename tuple_element<_I0, _T0>::type>::type&&...> type;
1505};
1506
1507template <class ..._Types, size_t ..._I0, class _Tuple0, class _Tuple1, class ..._Tuples>
1508struct __tuple_cat_return_ref_imp<tuple<_Types...>, __tuple_indices<_I0...>,
1509                                  _Tuple0, _Tuple1, _Tuples...>
1510    : public __tuple_cat_return_ref_imp<
1511         tuple<_Types..., typename __apply_cv<_Tuple0,
1512               typename tuple_element<_I0,
1513                  typename remove_reference<_Tuple0>::type>::type>::type&&...>,
1514         typename __make_tuple_indices<tuple_size<typename
1515                                 remove_reference<_Tuple1>::type>::value>::type,
1516         _Tuple1, _Tuples...>
1517{
1518};
1519
1520template <class _Tuple0, class ..._Tuples>
1521struct __tuple_cat_return_ref
1522    : public __tuple_cat_return_ref_imp<tuple<>,
1523               typename __make_tuple_indices<
1524                        tuple_size<typename remove_reference<_Tuple0>::type>::value
1525               >::type, _Tuple0, _Tuples...>
1526{
1527};
1528
1529template <class _Types, class _I0, class _J0>
1530struct __tuple_cat;
1531
1532template <class ..._Types, size_t ..._I0, size_t ..._J0>
1533struct __tuple_cat<tuple<_Types...>, __tuple_indices<_I0...>, __tuple_indices<_J0...> >
1534{
1535    template <class _Tuple0>
1536    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1537    typename __tuple_cat_return_ref<tuple<_Types...>&&, _Tuple0&&>::type
1538    operator()(tuple<_Types...> __t, _Tuple0&& __t0)
1539    {
1540        (void)__t; // avoid unused parameter warning on GCC when _I0 is empty
1541        return _VSTD::forward_as_tuple(
1542            _VSTD::forward<_Types>(_VSTD::get<_I0>(__t))...,
1543            _VSTD::get<_J0>(_VSTD::forward<_Tuple0>(__t0))...);
1544    }
1545
1546    template <class _Tuple0, class _Tuple1, class ..._Tuples>
1547    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1548    typename __tuple_cat_return_ref<tuple<_Types...>&&, _Tuple0&&, _Tuple1&&, _Tuples&&...>::type
1549    operator()(tuple<_Types...> __t, _Tuple0&& __t0, _Tuple1&& __t1, _Tuples&& ...__tpls)
1550    {
1551        (void)__t; // avoid unused parameter warning on GCC when _I0 is empty
1552        typedef _LIBCPP_NODEBUG typename remove_reference<_Tuple0>::type _T0;
1553        typedef _LIBCPP_NODEBUG typename remove_reference<_Tuple1>::type _T1;
1554        return __tuple_cat<
1555            tuple<_Types...,
1556                  typename __apply_cv<_Tuple0, typename tuple_element<
1557                                                   _J0, _T0>::type>::type&&...>,
1558            typename __make_tuple_indices<sizeof...(_Types) +
1559                                          tuple_size<_T0>::value>::type,
1560            typename __make_tuple_indices<tuple_size<_T1>::value>::type>()(
1561            _VSTD::forward_as_tuple(
1562                _VSTD::forward<_Types>(_VSTD::get<_I0>(__t))...,
1563                _VSTD::get<_J0>(_VSTD::forward<_Tuple0>(__t0))...),
1564            _VSTD::forward<_Tuple1>(__t1), _VSTD::forward<_Tuples>(__tpls)...);
1565    }
1566};
1567
1568template <class _Tuple0, class... _Tuples>
1569inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1570typename __tuple_cat_return<_Tuple0, _Tuples...>::type
1571tuple_cat(_Tuple0&& __t0, _Tuples&&... __tpls)
1572{
1573    typedef _LIBCPP_NODEBUG typename remove_reference<_Tuple0>::type _T0;
1574    return __tuple_cat<tuple<>, __tuple_indices<>,
1575                  typename __make_tuple_indices<tuple_size<_T0>::value>::type>()
1576                  (tuple<>(), _VSTD::forward<_Tuple0>(__t0),
1577                                            _VSTD::forward<_Tuples>(__tpls)...);
1578}
1579
1580template <class ..._Tp, class _Alloc>
1581struct _LIBCPP_TEMPLATE_VIS uses_allocator<tuple<_Tp...>, _Alloc>
1582    : true_type {};
1583
1584template <class _T1, class _T2>
1585template <class... _Args1, class... _Args2, size_t ..._I1, size_t ..._I2>
1586inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
1587pair<_T1, _T2>::pair(piecewise_construct_t,
1588                     tuple<_Args1...>& __first_args, tuple<_Args2...>& __second_args,
1589                     __tuple_indices<_I1...>, __tuple_indices<_I2...>)
1590    :  first(_VSTD::forward<_Args1>(_VSTD::get<_I1>( __first_args))...),
1591      second(_VSTD::forward<_Args2>(_VSTD::get<_I2>(__second_args))...)
1592{
1593}
1594
1595#if _LIBCPP_STD_VER > 14
1596template <class _Tp>
1597inline constexpr size_t tuple_size_v = tuple_size<_Tp>::value;
1598
1599#define _LIBCPP_NOEXCEPT_RETURN(...) noexcept(noexcept(__VA_ARGS__)) { return __VA_ARGS__; }
1600
1601template <class _Fn, class _Tuple, size_t ..._Id>
1602inline _LIBCPP_INLINE_VISIBILITY
1603constexpr decltype(auto) __apply_tuple_impl(_Fn && __f, _Tuple && __t,
1604                                            __tuple_indices<_Id...>)
1605_LIBCPP_NOEXCEPT_RETURN(
1606    _VSTD::__invoke(
1607        _VSTD::forward<_Fn>(__f),
1608        _VSTD::get<_Id>(_VSTD::forward<_Tuple>(__t))...)
1609)
1610
1611template <class _Fn, class _Tuple>
1612inline _LIBCPP_INLINE_VISIBILITY
1613constexpr decltype(auto) apply(_Fn && __f, _Tuple && __t)
1614_LIBCPP_NOEXCEPT_RETURN(
1615    _VSTD::__apply_tuple_impl(
1616        _VSTD::forward<_Fn>(__f), _VSTD::forward<_Tuple>(__t),
1617        typename __make_tuple_indices<tuple_size_v<remove_reference_t<_Tuple>>>::type{})
1618)
1619
1620template <class _Tp, class _Tuple, size_t... _Idx>
1621inline _LIBCPP_INLINE_VISIBILITY
1622constexpr _Tp __make_from_tuple_impl(_Tuple&& __t, __tuple_indices<_Idx...>)
1623_LIBCPP_NOEXCEPT_RETURN(
1624    _Tp(_VSTD::get<_Idx>(_VSTD::forward<_Tuple>(__t))...)
1625)
1626
1627template <class _Tp, class _Tuple>
1628inline _LIBCPP_INLINE_VISIBILITY
1629constexpr _Tp make_from_tuple(_Tuple&& __t)
1630_LIBCPP_NOEXCEPT_RETURN(
1631    _VSTD::__make_from_tuple_impl<_Tp>(_VSTD::forward<_Tuple>(__t),
1632        typename __make_tuple_indices<tuple_size_v<remove_reference_t<_Tuple>>>::type{})
1633)
1634
1635#undef _LIBCPP_NOEXCEPT_RETURN
1636
1637#endif // _LIBCPP_STD_VER > 14
1638
1639#endif // !defined(_LIBCPP_CXX03_LANG)
1640
1641_LIBCPP_END_NAMESPACE_STD
1642
1643#endif // _LIBCPP_TUPLE
1644